sometimes known as tits on a bull. An interrupt phrase that acts as an aside to the main subject and is set off in parenthesis (). The same effect can be achieved by employing a typographical em-dash ( — ) which I've enclosed parenthetically. While the em-dash creates a pause, a breath and then a continuance, parathesis, although grammatically correct, generally disrupts the flow of a sentence for most readers.
Edward C. Patterson